It is difficult to be certain from this short excerpt, but it seems possible that the writer of the letter intends to disparage the Occupy protestors. He or she "praises" them for their "sacrifices," but then cites examples of sacrifices that don't seem all that major, when compared to what members of other movements had to face. While nobody wants to fail an exam, it is not exactly a matter of life and limb. Read this way, it is in keeping with a common criticism of the Occupy protestors, i.e. that they were not serious about their message and, as largely middle-class white youths, could not speak for people who were poor and uneducated. The reference to "squats" could refer to their temporary villages in public spaces, but it also could be the foreclosed homes that many Occupy protestors took up residence in. Again, we can't be sure that the writer is not sincere, but this excerpt could be interpreted as a sarcastic critique of the protestors.